Oven-thermo meter



(No- .Model.)

P. ALLEN. OVEN THERMOMETER. No. 420.568. n

M Aheb. 4. 1890.

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UNITED STATES PATENT OEEICE.

FRANCIS ALLEN, OF KANSAS CITY, KANSAS.

OVEN-THERMOMETER.

SPECIFICATION forming part of Letters Patent No. 420,568, dated February 4, 1890.

Application filed July 8, 1889. Serial No. 316,787. (No model.)

To all whom it may concern.-

Be it known that I, FRANCIS ALLEN, a citizen of the United States, residing at Kansas City, in the county of Wyandotte and State of Kansas, have invented lcertain new and useful Improvements in Automatic Heat Regulators and Indicators; and I 'do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The invention relates to an automatic heat regulator and indicator, more' especially adapted for use in connection with ovens of`v door, showing my invention secured thereto, Flg. 2 isY a similar view of theV in position. opposite side of ovendoor, showing the indicator and valve.

In the drawings, A denotes an oven-door, to the inner side of which is journaled a train of gear, consisting in this instance of the cog-wheels B, C, and D. The arbors of the wheels C and D are provided each with a pinion c and d, respectively. The oven-door is provided with a rotary valve E, the arbor of which is also provided with a pinion e. An indicator-iinger is secured to the opposite end of the arbor of the wheel C, and is made to rotate around a dial-plate F, secured to the outer siderof the oven-door and suitably graduated.

It will be observed that when rotary motion is imparted to the wheel'B, the teeth of which engage' the pinion c, the wheel C, which is in y mesh with the pinion d, will be rotated, and in turn will rotate Wheel I), which, through in position by keepers h.

its engagement with the pinion upon the rotary valve, will rotate said valve. The indicatoringer will also be rotated during this operation around the indicator-plate.

A rod H, of copper or other suitable material rendered expansible by heat, is seated upon a step a, secured to the inner side of the oven-door, and has its upper end in engagement with a step a,secured to the Wheel B to one side of its center. The rod is held A similar step a2 is secured above this wheel to the door, and affords a seat for the upper end of a spring, (shown in this instance as la coil-spring) which has its lower end in engagement with the upper side of the seat a. The energy of this spring is exerted to force the wheel B in a direction opposite to that caused bythe expansion of the rod I-I.

A set-screw I has an engagement with the step o, for the purpose of adjusting the expansible bar vertically, the object of which will presently appear.

The operation of the device is as follows:

AIn cooking articles--as, for instance, in baking bread-the expansible rod is adjusted vertically by the set-screw until the gear is rotated a distance to bring the indicator- `finger opposite 380O Fahrenheit, marked on theindicator-plate, which is found to be i suiiicient heat to bake with. Vhen the heat Ywithin the oven reaches a point above 3800,

the valve, due to the expansion of the rod, will have rotated sufficiently to admit cold air within the oven, which will cool the bar and cause it to contract. The spring will then exert its force downward until the valve is closed and the step a on the wheel B coni tacts with the upper end of the rod.

It is obvious that in cooking other articles requiring greater or less heat the indicator will be set accordingly.

VHaving thus fully described my invention, I claim In combination, an oven-door, a train of .gearing journaled thereon, a damper journaled in saidA door and connected with' said gearing, an indicator-plate secured .to said door, an indicator-finger journaled in said door and connected with said gearing, steps step and the step of the gear, and means for secured to said door, respectively, near the adjusting said rod, substantially as set; forth. Io upper and lower edges of the same, a step In testimonywhereoflaffixmysignature in Secured to one of the gears at a point from presence of two Witnesses. 5 its Center, an expansible and oontraotible l FRANCIS ALLEN.

rod engaged with the lower step and with Witnesses: the step upon the gear, a spring having its BESSIE E. YOUNG, ends engaged, respectively, with the upper PERRY C. PHILLIPS. 

